unproblem: plot3 only displays one curve in 2.1

[Jordi Gutierrez Hermoso]

I thought that Octave would be good for drawing some phase portraits
of simple 3d linear dynamical systems (only one node at the origin),
but I'm running into problems with the Octave-forge function plot3.

Specifically, plot3 refuses to plot more than one curve in the same
plot. Instead, it plots each curve one at a time and erasing the
previous curve, as if "hold off" were in effect.

I suspected foul play from my .gnuplot file, but after I renamed it to
a backup, effectively having no .gnuplot file, the problem persisted.
For the record, usually the only commands I have in my .gnuplot are
"set pm3d" and "set mouse".

The following commands, for instance, only plot one helix of radius 2,
instead of two concentric helices:

    octave:1> t = [0:8*pi/80:8*pi]';
    octave:2> x = [cos(t), 2*cos(t)];
    octave:3> y = [sin(t), 2*sin(t)];
    octave:4> z = [t,t];
    octave:5> plot3(x,y,z)

... later...

Oh, well, this problem only seems to happen with the 2.1 branch of
Debian's Octave. After an apt-get update and apt-get installl
octave2.9, the problem went away.

Current setup, in case anyone's interested:


    address@hidden:~$ apt-cache policy octave2.1 octave2.9 octave-forge

    octave2.1:
      Installed: 1:2.1.73-8
      Candidate: 1:2.1.73-8
      Version table:
     *** 1:2.1.73-8 0
            990 http://debian.lcs.mit.edu testing/main Packages
            500 http://debian.lcs.mit.edu unstable/main Packages
            100 /var/lib/dpkg/status

    octave2.9:
      Installed: 2.9.6-3
      Candidate: 2.9.6-3
      Version table:
     *** 2.9.6-3 0
            500 http://debian.lcs.mit.edu unstable/main Packages
            100 /var/lib/dpkg/status
         2.9.4-13+b1 0
            990 http://debian.lcs.mit.edu testing/main Packages

    octave-forge:
      Installed: 2006.03.17-2
      Candidate: 2006.03.17-2
      Version table:
     *** 2006.03.17-2 0
            990 http://debian.lcs.mit.edu testing/main Packages
            500 http://debian.lcs.mit.edu unstable/main Packages
            100 /var/lib/dpkg/status

Er, I hope I didn't annoy anyone by talking here about a problem that
I fixed with a simple update. Thanks to whomever changed something in
the 2.9 branch that fixed the problem.

- Jordi G. H.